Apparatus for starting and operating gaseous discharge devices



NM Km v F. w. ABRAHAMS Filed Dec. 28, 1954 APPARATUS FOR STARTING ANDOPERATING GASEOUS DISCHARGE DEVICES Jan. 20, 1959 United States PatentAPPARATUS FUR STARTING AND OPERATING GASEOUS DISCHARGE DEVICES Fred W.Abrahams, Chicago, 111., assignor to Advance Transformer (30., Chicago,111., a corporation of Illinois Application December 28, 1954, SerialNo. 477,989

13 Claims. (Cl. 315-97) This invention relates generally to apparatusfor starting and operating gaseous discharge devices, and particularlyis concerned with such a device known as a ballast, which has unusualpower factor correcting ability.

Generally the invention contemplates a ballast which is intended toserve two gaseous discharge devicesfluorescent lamps in the particularapplication for the apparatus built in accordance with theinvention-connected in series.

Objects of the invention are: the provision of a ballast in which theamount of iron and necessary copper are held to a minimum; the provisionof a ballast in which power factor correction is achieved in a novelmanner due to the unusual arrangement of the windings on the core; theprovision of a device in which power factor correction is achievedthrough the use of a smaller condenser than would ordinarily be used;and the provision of a device of the character described which isintended for use with gaseous discharge devices of the rapid start type,that is, for example, fluorescent lamps in which the filaments havecurrent flowing therein continuously.

Further important objects are: the provision of a series connected pairof gaseous discharge devices in which there is a capacitance connectedacross one of the devices to aid in starting and in which there iscapacitive means connected across the primary winding; the provision ofa power factor correcting circuit for series connected discharge devicesin which there is a current limiting impedance in series with thediscarge devices, but in which there is no capacitance in the operatingcurrent circuit for the lamps; the provision of a circuit for ignitingand operating gaseous discharge devices in which the primary is dividedinto two parts each of which is coupled in different degree to thesecondary winding supplying the principal voltage for the dischargedevices; the provision of a gaseous discharge device apparatus in whichthe windings are arranged relative to a shell core in a novel manner toachieve certain beneficial results.

Other objects will appear as the description of the invention proceeds,in connection with which there has been illustrated in considerabledetail a preferred embodiment of the invention demonstrating the mannerin which the same is carried into practical use and application.

In the drawing, in which none of the conventional core and shunt linesare shown in order to keep the illustration uncluttered:

Fig. 1 is an electrical circuit diagram of the apparatus of theinvention.

Fig. 2 is a side elevational view of the transformer portion of theapparatus illustrated in Fig. 1.

The invention resides principally in the power factor correcting circuitand in the arrangement of the windings upon the transformer core, andhence it would perhaps be best to describe first the transformer and itswindings.

As seen in Fig. 1 there are three filament windings F F and F there aretwo primary windings P and P and there are three secondary windings S Sand S The windings P and S and closely coupled together, being PatentedJan. 20, 1959 wound on top of one another in a window of the transformercore as will be seen; the windings P S and F are also closely coupledtogether and wound one on top of another in the second window of thetransformer core; and the windings S F and F are also closely coupledtogether and wound one on top of the other in a window of thetransformer core. The relationships between the various groups ofwindings will shortly be brought out.

The transformer 10 comprises a stack of identical laminations ofelectrical sheet steel forming an outer shell 12 of rectangularformation and an inner winding leg 14 which extends the length of theshell 10 on the interior thereof. The laminations are held together byriveting or the like as indicated at 16, and the central winding leglaminations are stamped out of the same blanks. The said central windingleg 14, after assembled with the windings, is pressed back into therectangular shell 12, with its curved ends matingly engaging at 18 and20 with the bridging ends 22 and 24 respectively of the shell 12. Properseating is obtained in any suitable manner such as for example, byjuxtaposed indexing notches 26.

There are several punched out portions along the core 10 between thewinding leg 14 and the elongate sides 28 and 3t spaced apart by inwardextensions 32 and 34 relatively narrow, and 36 and 38 relatively wide.The designated extensions are all integral with the shell 12, the formerpair extending about halfway to the winding leg and there facingsimilarly aligned extensions 40 and 42 integral with the winding leg.The extensions 32, 34, 40 and 42 together form a magnetic shunt whichwill generally be designated 43, provided with non-magnetic spaced gapsS4 of high reluctance. The extensions 35 and 38 face notches 56 and 48cut in the winding leg 14 being spaced therefrom by gaps 50 and therebyforming the magnetic shunt 52 with non-magnetic high reluctance gaps.The particular structure aids in placement of the windings on thevarious parts of the winding leg 14 prior to pressing same home into thecore 12.

Between the shunt 43 and the bridging end 22 there are formed windows54; between the shunts 43 and 52 there 3 are formed windows 55; andbetween the shunt 52 and the bridging end 24 there are formed windows56. The windings P and S are both in the windows 54; the windings P Sand F are all in windows 55; and the windings S F and F are all inwindows 56. Conveniently, the winding F may be a continuation of thewinding P and the winding F a continuation of winding S Connections areobtained by suitable taps.

The windings P and P actually form together a primary winding which hasbeen split into two parts separated by the shunt 4-3 since both are inseries and connected to terminals and 61. The series connection betweenprimary parts P and P is provided by jumper 64, the right hand terminalof the primary winding P P is designated and the left hand terminal 66.The two gaseous discharge devices L and L are of the continuous currentfilament type, the illustration intended to designate rapid startfluorescent lamps. Each lamp has a filament at opposite ends which mustbe continuously energized. L has filament 67 connected by leads 68 and69 across Winding P; which provides a voltage induced by primary windingpart P and a second filament 73 connected in parallel with the filament71 of the discharge device L Jumpers 73 and '74 are connected byrespective leads 75 and 76 with filament winding F which is intransformer relation with winding S The filament 78 is connected acrossfilament winding F by leads 79 and S0.

The secondary winding S is connected by lead 82 to terminal 66 andconnects with junction point 84. Between junction point 34 and terminal65 there is connected a power factor winding 8;, in series with a powerfactor condenser C This winding is of particular interest be- 3 cause ofits unusual function which presently will be brought out.

The third secondary winding S is connected by way of lead 86 betweenjunction point 84 and terminal 88 which it has in common with filamentwinding F The basic operating circuit is a series circuit including thetwo discharge devices L and L and the two secondary windings S and S inauto-transformer relationship with the primary windings P and P Theseries circuit extends from terminal 66, includes winding S lead 86,winding S winding F (giving an additional few volts to the seriescircuit for aid in starting), lead 84}, filament 73, discharge device Lfilament 71, jumper 73, filament 7t), discharge device L filament 67,lead 69, filament winding F to terminal 65, Note that the arrowsalongside the respective windings indicate the instantaneous voltagesense which is additive as to I the windings.

There is a shunting condenser C across the discharge device L so thatupon energization of the circuit the discharge device L will ignitefirst, after which the voltage across the condenser C will build upbecause of current flow. The ignitionof 1. then occurs and currentby-passes through the discharge device so that the capacitive effect or"C is not in the circuit.

Now it will be seen that there are basically three sections to thetransformer formed of the various grouping of windings heretoforedescribed. The first section is composed of the first primary part P andthe first secondary S The voltage induced in the secondary S contributesboth as to the ignition and operation of the-discharge devices. Thesecond primary part P and the second secondary winding S together withthe filament winding F form the grouping of the second section. There isa shunt 43 between the first and second sections such that the couplingbetween them is loose, but not to the extent that the coupling betweenthird and second sections is loose. The shunt 52 is better than fourtimes as wide as shunt 43 and obviously the coupling between secondsection and the third section, which comprises only the third secondarywinding S and the remaining filament windings, is much looser thanbetween the first and second sections. This ratio may be even greater ifdesired.

The winding S is arranged as described, so that there will be a greatdeal of leakage reactance affecting the same during operation. This isthe current limiting means required to give good regulation to thedischarge devices, which have negative resistance characteristics whenoperating. The core is non-saturating in the vicinity of winding S toprevent distortion of wave shape.

Speaking of distortion and wave shape, for maximum light it is best toavoid capacitive current and its accompanying distortion of wave shape.Capacitive current, for example, more readily saturates iron. If acircuit which is a simple series operating circuit for a pair of gaseousdischarge device L and L as here is energized in the conventional way,and it is desired to correct for power factor, it is necessary to placecapacitance in series with the discharge devices. The result is adistorted current through the discharge devices with decrease inlighting efficiency.

It is believed that the novelty of the invention extends to the use of acapacitive circuit across the primary in combination with a seriescircuit having one discharge device shunted by a starting capacitor, butin any event, the mere use of a capacitor between the junction point 84and terminal 65 would not be totally satisfactory. The reason is thatthe capacitance would have to be so high that the size and cost of thecapacitor would eliminate the use of such apparatus.

Several reasons are believed to account for the high efiiciency of theapparatus of the invention, considering its'cost and size. First,- thesecond section serves d to isolate the primary part P and its closelycoupled secondary S from the mutual inductive effects of the thirdsection during operation. Thus a greater voltage is capable of beingdeveloped in P and S than would ordinarily be developed without theisolating section. Second, the winding S in series with the capacitor Caiiects the primary winding P P but has no distorting eifect upon theprincipal discharge device circuit since it is in parallel with aportion of same. Thirdly, the winding S being closely coupled with theprimary P provides additive voltage for igniting and operating thedischarge devices without inductive reactance of any great amount andhence need not be compensated for insofar as power factor is concerned.Furthermore, it provides additional voltage for the power factorcorrecting condenser C keeping its capacitance low.

The sectional separation of the windings has produced a highly desirableapparatus. The wave shape is very close to sinusoidal and saturation ofthe core is a minimum. The power factor correction ability,notwithstanding the small condenser used (see example below) is believedaccountable by virtue of isolation of the first section from the thirdby the second.

A practical effect of the sectionalization as described is the makingavailable of winding space without the necessity of crowding.

It has been found that through the use of the invention a. smaller andmore economical ballast has been evolved than presently being made forthe same requirements, and with an increase in lighting efliciency overothers. Some attempt has been made to explain this by logical theory,but it is desired to emphasize that this has been only to aid infollowing the description. The invalidity of such theories, althoughsincere effort has been put into the working out of the same, in nowisewould detract from the stature of the invention as represented by thestructure described. Certainly the salutary results are due to a novelcombination whose precise interaction; may be incapable of explanationeven by the most learned in this empirical and complex field. Because ofthis, the scope of the appended claims is intended to be limited onlythrough the consideration of the novelty of the structures describedtherein in the light of pertinent prior art.

It is believed that one skilled in the art to which this inventionappertains will have no difliculty in readily working out the details ofa working example of apparatus embodying the invention through theexplanation given above, but in order to assuage any possible doubt acommercial version of the invention will be described hereinafter.

The apparatus described was intended for the ignition and operation oftwo 96 inch watt fluorescent lamps each of the rapid start type, ratedat 893 milliamperes current, and one and one half inches in diameter(T-12). The number of turns and wire size were as follows:

P 258 turns, 19 gauge. P turns, 19 gauge. S 670 turns, 25 gauge. S 351turns, 23 gauge. 8;; 815 turns, 23 gauge.

The filament windings were between 14 and 16 turns of 19 or 23 gaugewire.

The capacitors were:

C 5.75 mfds, 400 volts A. Q. C n, .075 mfds, 800 volts A. C.

The proportions of the drawing with respect to the dimensions of thelaminations are approximately right. The long dimension was 7.8" and thewide dimension 3". The stack height was 1% inches. Gaps 44 were .027 andgaps 50 were .058".

viously all voltages are A. C.

The device operates in this manner: When the primary P P is energized, avoltage will appear across the lamp L which is sufficient to ignite thelamp L Because of the condenser C shunting the lamp L the entire voltageacross both lamps will be available for the lamp L; by itself. Thisvoltage in the particular example is approximately 515 volts. It isachieved as a result of the additive effects of the primary windings andthe windings S and S Once L is ignited, current flows through the serieslamp circuit, except that no current is flowing through lamp L The flowof current through the condenser C causes a voltage to appear acrossthat condenser of sufficient value to ignite lamp L after which thecondenser C is short-circuited by the low impedance of the lamp L whilesame is operating.

After current flows through winding S because it is separated from theremaining principal windings by a rather large shunt, a high leakagereactance develops, acting as a deterrent to current flow. This keepsthe lamps from destroying themselves, limiting the current to the ratedvalue.

The voltages in the various parts of the apparatus are of interest inthat they assist in visualizing the operation of the device.

For a line voltage, that is, a voltage across the primary parts P and Pcombined, of 118 volts the following voltages will exist:

Across the filament windings the voltage is from 4.0 to 4.1 volts onopen circuit, and this drops to 3.8 volts during operation, except forthe voltage across F which was found to be 3 volts.

Line current was 2.1 amperes, lamp current was the rated 800milliamperes, current through the primary winding was 1.7 amperes, andcurrent through the capacitive circuit including C was 850rnilliamperes.

The above apparatus gave excellent performance, both by way of goodpower factor correction and efiiciency of lighting.

It is believed that the invention has been fully described in such amanner as not to require additional explanation.

What it is desired to secure by Letters Patent of the United States is:

1. Apparatus for igniting and thereafter providing the operatingvoltages for gaseous discharge devices which comprises: a pair ofgaseous discharge devices one of which has a condenser shunting the sameand the discharge devices being connected in series so that they willignite in sequence by virtue of said condenser, a source of A. C. powerof voltage less than that required to ignite either discharge device, atransformer having an elongate iron core, a primary winding on the coreat one end thereof and connected across the source, a high leakagereactance secondary winding mounted at the other end of the core, ashunt separating the primary winding and the high leakage reactancesecondary winding to provide the high leakage reactance duringoperation, the secondary and primary windings being in autotransformerrelationship and connected across the two gaseous discharge devices inseries, and a capacitive circuit connected across the primary windingfor power factor correction, said capacitive circuit comprising a secondcondenser and a second secondary winding mounted on said transformercore and closely coupled to the primary winding, the capacitive circuitbeing in parallel with a loop including the first mentioned secondarywinding combined with said gaseous discharge devices.

2. Apparatus for igniting and thereafter providing the operatingvoltages for gaseous discharge devices which comprises: a pair ofgaseous discharge devices one of which has a condenser shunting the sameand the discharge devices being connected in series so that they willignite in sequence by virtue of said condenser, 21 source of A. C. powerof voltage less than that required to ignite either discharge device, atransformer having an elongate iron core, a primary winding on the coreat one end thereof and connected across the source, a high leakagereactance secondary winding mounted at the other end of the core, ashunt separating the primary winding and the high leakage reactancesecondary winding to provide the high leakage reactance duringoperation, the secondary and primary windings being in autotransformerrelationship and connected across the two gaseous discharge devices inseries, and a capacitive circuit connected across the primary windingfor power factor correction, said capacitive circuit comprising a secondcondenser and second and third secondary windings, the third secondarywinding being in additive voltage relation with the primary winding andfirst mentioned secondary winding whereby said auto-transformerrelationship includes the voltage thereof.

3. Apparatus for igniting and thereafter providing the operatingvoltages for gaseous discharge devices which comprises: a pair ofgaseous discharge devices one of which has a condenser shunting the sameand the discharge devices being connected in series so that they willignite in sequence by virtue of said condenser, a source of: A. C. powerof voltage less than that required to ignite either discharge device, atransformer having an elongate iron core, a primary winding on the coreat one end thereof and connected across the source, a high leakagereactance secondary winding mounted at the other end of the core, ashunt separating the primary winding and the high leakage reactancesecondary winding to provide the high leakage reactance duringoperation, the secondary and primary windings being in auto-transformerrelationship and connected across the two gaseous discharge devices inseries, and a capacitive circuit connected across the primary windingfor power factor correction, the capacitive circuit comprising a secondcondenser and second and third secondary windings all connected inseries, the first mentioned secondary winding being connected to thecapacitive circuit dividing same into two branches one being the thirdsecondary winding and the other being the second secondary winding andsecond condenser in series, the third secondary winding being in voltageadditive relation with the first secondary winding so that the voltagedeveloped in said third secondary winding is available for ignition andoperation in addition to those developed in said primary winding andfirst secondary winding.

4. Apparatus as claimed in claim 3 in which said transformer hasfilament windings coupled with windings thereof, and said gaseousdischarge devices have filaments connected to said filament windings.

5. Apparatus for igniting and thereafter providing the operatingvoltages for gaseous discharge devices which comprises: a pair ofgaseous discharge devices one of which has a condenser shunting the sameand the discharge devices being connected in series so that they willignite in sequence by virtue of said condenser, a source of A. C. powerof voltage less than that required to ignite either discharge device, atransformer having an elongate iron core, a primary winding on the coreat one end thereof and connected across the source, a high leakagereactance secondary winding mounted at the other end of the core, ashunt separating the primary winding and the high leakage reactancesecondary winding to provide the high leakage reactance duringoperation, the secondary and primary windings being in auto-transformerrelationship and connected across the two gaseous discharge devices inseries, and a capacitive circuit connected across the primary windingfor power factor correction, the primary winding being composed of twoparts, and there is a second shunt between the parts.

6. Apparatus as claimed in claim in which one part, having substantiallyless turns than the other, is disposed between the said other part andthe said secondary winding.

7. Apparatus for igniting and thereafter providing the operatingvoltages for gaseous discharge devices which comprises: a pair ofgaseous discharge devices one of which has a condenser shunting the sameand the discharge devices being connected in series so that they willignite in sequence by virtue of said condenser, a source of A. C. powerof voltage less than that required to ignite either discharge device, atransformer having an elongate iron core, a primary winding on the coreat one end thereof and connected across the source, a high leakagereactance secondary winding mounted at the other end of the core, ashunt separating the primary winding and the high leakage reactancesecondary winding to provide the high leakage reactance duringoperation, the secondary and primary windings being in auto-transformerrelationship and connected across the two gaseous discharge devices inseries, and a capacitive circuit connected across the primary windingfor power factor correction, the primary winding being composed of twoseries connected parts loosely coupled together, the capacitive circuitincluding a second secondary winding and condenser, the second secondarywinding being closely coupled to one of said parts.

8. Apparatus for igniting and thereafter providing the operatingvoltages for gaseous discharge devices which comprises: a pair ofgaseous discharge devices one of which has a condenser shunting the sameand the discharge devices being connected in series so that they willignite in sequence by virtue of said condenser, a source of A. C. powerof voltage less than that required to ignite either discharge device, atransformer having an elongate iron core, a primary winding on the coreat one end thereof and connected across the source, a high leakagereactance secondary winding mounted at the other end of the core, ashunt separating the primary winding and the high leakage reactancesecondary winding to provide the high leakage reactance duringoperation, the secondary and primary windings being in auto-transformerrelationship and connected across the two gaseous discharge devices inseries, and a capacitive circuit connected across the primary windingfor power factor correction, the primary winding being composed of twoseries connected parts loosely coupled one to the other on saidtransformer core, the capacitive circuit including two additionalsecondary windings and a capacitor, the said additional secondarywindings being closely coupled with the respective parts, and the firstmentioned secondary winding being connected in additive relationshipwith one of said additional secondary windings.

9. Apparatus as claimed in claim 8 in which the first mentionedsecondary winding is connected to the capacitive circuit dividing thesame into two branches one of which consists of the additional secondarywinding with which it is in additive relation.

10. Apparatus for igniting and thereafter providing the operating voitaes for gaseous discharge devices which comprises: a pair of gaseousdischarge devices one of 6 which has a condenser shunting the same andthe discharge devices being connected in series so that they will ignitein sequence by virtue of said condenser, a source of A. C. power ofvoltage less than that required to ignite either discharge device, atransformer having an elongate iron core, a primary winding on the coreat one end thereof and connected across the source, a high leakagereactance secondary winding mounted at the other end of the core, ashunt separating the primary winding and the high leakage reactancesecondary winding to provide the high leakage reactance duringoperation, the secondary and primary windings being in autotransformerrelationship and connected across the two gaseous discharge devices inseries, and a capacitive circuit connected across the primary windingfor power factor correction, the core having three windows along itslength, a second shunt being disposed between the first and secondwindows and being substantially smaller than the said first mentionedshunt which is disposed between the second and third windows, theprimary Winding comprising two parts, one of which is disposed in eachof the first and second windows respectively with the said firstsecondaryivinding in the third window.

11. Apparatus as claimed in claim 9 in which the capacitive circuit.includes a second secondarry winding which is disposed in the firstwindow along with said one part, and a condenser in series therewith.

12. Apparatus as claimed in claim 9 in which the capacitive circuitincludes second and third secondary windings disposed respectively inthe first and second windows, a capacitor in series with the said secondand third secondary windings, and the first secondary winding beingconnected in additive voltage relation only with the said secondsecondary winding.

13. Apparatus for igniting and thereafter providing the operatingvoltage for gaseous discharge devices which comprises: a pair of gaseousdischarge devices one of which has a starting aid condenser shunting thesame and the discharge devices being in series so that they will ignitein sequence by virtue of said condenser, a source of A. C. power ofvoltage less than that required to ignite either discharge device, atransformer having an elongate iron core with three winding sectionsthereon, the first section on one end comprising a first primary windingpart and a first secondary winding, the second section in the middlecomprising a second primary winding part and a second secondary winding,and the third section at the second end comprising a third secondarywinding, shunts with non-magnetic gaps between sections and the shuntbetween second and third sections being wider than the other shunt, theprimary parts being connected across the source, a power factorcondenser and said first and second secondary windings being in seriesand together connected across the primary parts as a shunting powerfactor circuit, the third secondary being in series with both dischargedevices and connected between one side of the source and the powerfactor circuit between first and secondary windings and inauto-transformer relation with both primary parts and only one of saidfirst and second secondary windings.

References Cited in the file of this patent UNITED STATES PATENTS UNITEDSTATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 2 ,8'70 1378January 2O, 1959 Fred W0 Abrahams It is hereby certified that errorappears in the printed specification of the above numbered patentrequiring correction and that the said Letters .Patent should read ascorrected below.

Column 8, lines 24 and 28, for the claim. refisrence numeral "9",, eachoccurrence, read m 1.0

Signed and {sealed this 5th day of May 1.9590

ism) t'test:

KARL Ha AXLINE ROBERT C. WATSON Attesting Officer Commissioner ofPatents Attesting Ofl'icer UNITED STATES PATENT OFFICE CERTIFICATE OFCORRECTION Patent No, 2,870,378 January 20., 1959 Fred W n Abrahams Itis hereby certified that error appears in the printed specification ofthe above numbered patent requiring correction and that the said LettersPatent should read as corrected below.

Column 8, lines 24 and 28, for the claim reference numeral "'9 eachoccurrence 9 read' PM 10 Signed and sealed this 5th day of May 1.959.

S AL) t'test:

KARL H, AXLINE ROBERT C. WATSON Commissioner of Patents

